There are a great many types of laundry additive materials suitable for use in automatic washing machines for fabric laundering. Cleaning agents such as surfactants and detergent builders are used to assist in the mechanical removal of soil and stains from fabrics being laundered. Bleaching agents, enzymes and adjuvants relating thereto are designed to promote chemical degradation and removal of soils and stains. Fabric conditioners, softeners, anti-wrinkle agents, soil release materials and similar agents serve to alter and enhance the condition, appearance or feel of laundered fabrics. Other auxiliary materials, such as pH adjustment and control agents, buffers, solvents, dispersants, anti-redeposition agents, dye transfer inhibitors, stabilizers, preservatives, perfumes, dyes and the like are used to alter the aqueous environment in the automatic washing machine drum to provide for optimum performance of the active laundry additive materials or to improve the quality or aesthetics of commercialized laundry products containing these active additive materials.
The several types of laundry additive materials described hereinbefore, frequently intermingled or admixed together in a wide variety of combinations for convenience, are commonly marketed to consumers in bulk quantities, in either solid, i.e., granular or tablet, or liquid form. To carry out the laundering operation, the consumer then adds aliquots of product as needed or desired from the bulk products into the automatic washing machine drum in appropriate amounts and at appropriate times during the laundering cycle.
It would be desirable, and a number of attempts have been made, to market fabric laundering products in “unit dose” form whereby aliquots of laundry additive materials are provided in pre-measured, pre-packaged form. The consumer can then conveniently add one of these unit dose aliquots to the automatic washing machine, e.g., into the drum, at the beginning of the laundry cycle and not have to measure product from bulk or add product to the cycle at different subsequent points in time.
Several factors complicate the provision of certain types of laundry additive materials in unit dose form. In the first place, some types and forms of laundry additives are not compatible with each other within a single concentrated product. Different types of materials may chemically interact with each other when admixed in concentrated form, thereby degrading and rendering one or both types ultimately ineffective for its intended purpose. Such incompatibility works against combining such materials together within a single unit dose product.
The major complicating factor in providing unit dose laundry products is that different types of laundry additives work best under different sets of conditions. Such different conditions are those which occur as the laundering operation progresses through its cycles which generally include washing and rinsing stages within the drum. The need therefore arises to add different types of laundry additives to the washing machine drum at different times during the laundering procedure. Most importantly, a number of types of fabric conditioners and softeners and other additives are best added to the rinse stages of the laundering operation. This is because many of these materials do not work in the way they are intended if they are present in the relatively high pH washing stages in the presence of chemically incompatible surfactants, builders, enzymes and other types of materials which perform their functions in the washing cycle(s). Thus even when provided in unit dose form, a number of materials which are typically thought of as rinse additives must be placed in the washing machine during the rinse cycle, well after the initial stages of the laundering operation have begun. This can create the need for the consumer to return to the washing machine at the beginning of the rinse cycle to add the materials which are to function during the rinsing operation.
A number of attempts have been made to permit the consumer to place rinse additive materials into devices or dispensers at the beginning of the laundering operation with those devices or dispensers serving to add the rinse additives to the rinse cycle automatically. Rinse addition can thus occur without further consumer involvement when the rinse cycle is reached later in the laundering operation. Many of such devices and dispensers operate by having their dispensing action activated by the centrifugal force. Centrifugal force, of course, arises as a consequence of the spin cycle in the machine laundering process. A fast spin cycle generally follows the washing step and serves to drain the washing machine drum of wash water prior to the addition of rinse water for the rinse cycle which follows the spin cycle.
Use of centrifugal force activated devices, dispensers or packages for delivery of rinse additives to the rinse cycles in an automatic laundering machine operation is not without its difficulties. In the first place, it is not simple or straightforward to fashion such devices, dispensers or packages in a way such that they are useful with or as unit dose packages of rinse additives. In the second place, systems utilizing unit dose packages of rinse additives must be designed so that the unit dose can survive the stresses and rigors of the washing stages of the laundering operation while remaining unopened and intact. Finally, the centrifugal force-activated dispensing means for the unit dose must be configured so that the unit dose of rinse additives is not added to the washing machine drum too soon after the spin cycle begins. If the rinse additive contents of the unit dose are released into the drum too early, much of these contents are lost with the wash water being drained from the drum during the spin cycle.
Given the foregoing difficulties in formulating unit dose products for use as rinse additives, it is an objective of the present invention to provide a system which can effectively utilize rinse additive products in unit dose form to deliver rinse adjuvants to the drum of an automatic fabric laundering machine during the rinse stage of its operational cycle. Such an objective is realized by providing a unit dose in the form of a certain type of rigid or flexible package. Such a package is then placed as an insert into a certain type of housing device which is positioned within the washing machine drum and which serves to bring about the desired manner and timing of dispensing of rinse additives into the washing machine drum for the rinse cycle.